Keyboard device for keyboard instrument

ABSTRACT

A keyboard device for a keyboard instrument, capable of causing a cushion to properly function while suppressing generation of noise when a hammer contacts the cushion. The hammer is vertically pivotally moved in a manner interlocked with key depression. The cushion is provided below the hammer. In a key-released state, a contact portion of the hammer is placed on the cushion, and when the hammer pivotally moved upward by key depression returns to its original position by key release, the contact portion contacts the cushion from above. The contact portion is formed to be inclined in the front or rear direction with respect to the upper surface of the cushion when contacting the cushion. The hammer has a deformation suppressing portion provided on the contact portion and/or its vicinity, for suppressing deformation of the cushion in the front-rear direction when contacting the cushion.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a keyboard device which is applied to akeyboard instrument, such as an electronic piano, and includes a hammerpivotally moved in a manner interlocked with key depression.

Description of the Related Art

Conventionally, as this type of a keyboard device, there has been known,for example, one disclosed in Japanese Laid-Open Patent Publication(Kokai) No. 2014-10374. In this keyboard device, hammers are pivotallymovably provided below keys extending in a front-rear direction, on akey-by-key basis. In a key-released state, each hammer extends in thefront-rear direction in a state inclined downward toward the rear suchthat a rear end thereof contacts a stopper from above. This stopper isformed by a stopper rail horizontally extending in a left-rightdirection, and a buffer formed on an upper surface of the stopper railand having a predetermined rectangular shape in transverse cross-sectionover the entire longitudinal length thereof.

In the keyboard device including the stopper described above, when oneof the keys is depressed, a hammer associated with the key is pivotallymoved in a predetermined direction, and a rear end of the hammer movesupward from the stopper. Then, when the key is released, the hammer ispivotally moved in a direction opposite to the above-mentioneddirection, and the rear end of the hammer moves into contact with thestopper from above.

In the keyboard device including the above-described hammers andstopper, when one of the hammers contacts the stopper, the contact of acontact portion of the hammer onto the buffer of the stopper fromimmediately above, the buffer having the rectangular shape in transversecross-section is deformed only in a vertical direction, so that thebuffer can properly exert its function as a buffer. However, if thecontact portion of the hammer has a large contact area at a moment whenthe contact portion of the hammer contacts the buffer, noise is liableto be generated. To avoid this, it is envisaged, for example, that anupper surface of the buffer is formed to extend horizontally, and thecontact portion of the hammer is formed such that the contact portion isinclined with respect to the horizontal upper surface, whereby thecontact area is prevented from being large at the moment when thecontact portion of the hammer contacts the buffer.

However, in the case where the upper surface of the buffer and thecontact portion of the hammer are formed as described above, when thecontact portion of the hammer contacts the buffer, not only a downwardforce but also a force in the front-rear direction acts on the bufferfrom the contact portion of the hammer. As a consequence, there is afear that the buffer is liable to be deformed in the front-reardirection, causing the buffer to be hindered from sufficiently exertingits function as a buffer.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a keyboard devicefor a keyboard instrument, which is capable of causing a cushion toproperly exert its function as a cushion while suppressing generation ofnoise when a hammer contacts the cushion.

To attain the above object, the present invention provides a keyboarddevice for a keyboard instrument, including a keyboard chassis, a keyextending in a front-rear direction and disposed on the keyboardchassis, a hammer extending in the front-rear direction and beingpivotally supported, below the key, on the keyboard chassis, via ahammer support shaft, the hammer being vertically pivotally moved in amanner interlocked with the key which has been depressed, and a cushionprovided below the hammer and having a predetermined portion of thehammer placed thereon in a key-released state, the predetermined portionof the hammer contacting the cushion from above when the hammer havingbeen pivotally moved upward in accordance with depression of the keyreturns to an original position in accordance with release of the key,wherein the predetermined portion of the hammer is formed such that thepredetermined portion is inclined downward toward one side in thefront-rear direction with respect to an upper surface of the cushionwhen the predetermined portion contacts the cushion, and wherein thehammer has a deformation suppressing portion provided on thepredetermined portion and/or its vicinity, for suppressing deformationof the cushion in the front-rear direction when the hammer contacts thecushion.

With this construction, when the hammer having been pivotally movedupward in accordance with depression of the key returns to its originalposition in accordance with release of the key, the predeterminedportion of the hammer contacts the cushion from above. In this case,since the predetermined portion of the hammer is formed such that thepredetermined portion is inclined downward toward one side in thefront-rear direction with respect to the upper surface of the cushion,the predetermined portion of the hammer progressively contacts the uppersurface of the cushion from one end toward the other end thereof in thefront-rear direction. With this, it is possible to suppress generationof noise when the hammer contacts the cushion. Further, when theabove-mentioned predetermined portion of the hammer contacts thecushion, not only a downward force but also a force in the front-reardirection sometimes acts on the cushion. In view of this, the hammer hasthe deformation suppressing portion provided on the predeterminedportion and/or its vicinity, and therefore, this deformation suppressingportion suppresses deformation of the cushion in the front-reardirection, thereby making it possible to cause the cushion to properlyexert its function as a cushion.

Preferably, the predetermined portion of the hammer is formed such thatthe predetermined portion is inclined downward toward a rear withrespect to the upper surface of the cushion when the predeterminedportion contacts the cushion, and the deformation suppressing portionincludes a downwardly protruding front-side protrusion on a front sideof the predetermined portion.

With the construction of this preferred embodiment, the predeterminedportion of the hammer is formed such that the predetermined portion isinclined downward toward the rear with respect to the upper surface ofthe cushion when the hammer contacts the cushion. Therefore, when thepredetermined portion of the hammer contacts the cushion, thepredetermined portion progressively contacts the cushion from a rear endtoward a front end of the cushion. In this case, although not only adownward force but also a force from the rear to the front acts on thecushion by the predetermined portion of the hammer, since the downwardlyprotruding front-side protrusion is formed on the front side of thepredetermined portion of the hammer, it is possible to effectivelysuppress forward deformation of the cushion.

More preferably, the deformation suppressing portion further includes adownwardly protruding rear-side protrusion on a rear side of thepredetermined portion.

With the construction of this preferred embodiment, the downwardlyprotruding rear-side protrusion is provided on the rear side of thepredetermined portion of the hammer, and therefore when thepredetermined portion of the hammer contacts the cushion, it is possibleto more effectively suppress deformation of the cushion in thefront-rear direction by cooperation of the downwardly protrudingrear-side protrusion and the front-side protrusion provided on the frontside of the predetermined portion of the hammer.

Preferably, the cushion is provided with a recess open upward at aportion corresponding to the predetermined portion of the hammer, andthe deformation suppressing portion includes a fitting protrusion formedon the predetermined portion such that the fitting protrusion has aprotruding shape protruding downward and is fittable in the recess.

With the construction of this preferred embodiment, while the recessopen upward is provided at the portion of the cushion corresponding tothe predetermined portion of the hammer, the fitting protrusion fittablein the recess of the cushion is formed on the predetermined portion ofthe hammer, as the deformation suppressing portion. With this, when thepredetermined portion of the hammer contacts the cushion, the fittingprotrusion of the hammer is fitted in the recess of the cushion, wherebyit is possible to suppress deformation of the cushion in the front-reardirection.

The above and other objects, features, and advantages of the presentinvention will become more apparent from the following detaileddescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are perspective views of a part (one octave section) ofa keyboard device for an electronic piano to which the present inventionis applied, in which FIG. 1A shows the appearance of the keyboard deviceand FIG. 1B shows a state in which keys other than a white key and ablack key at a left end of the keyboard device are omitted;

FIG. 2 is a perspective view of the keyboard device shown in FIG. 1B ina state in which the white key and the black key are removed, togetherwith respective key support mechanisms therefor, from a keyboardchassis;

FIG. 3A is a plan view of the keyboard device shown in FIG. 1B and FIG.3B is a cross-sectional view taken along line A-A of FIG. 3A;

FIGS. 4A and 4B are perspective views of the white key and the keysupport mechanism therefor, in which FIG. 4A shows the white key and thekey support mechanism in a connected state and FIG. 4B shows the whitekey and the key support mechanism in an exploded state;

FIGS. 5A and 5B are perspective views of the black key and the keysupport mechanism therefor, in which FIG. 5A shows the black key and thekey support mechanism in a connected state and FIG. 5B shows the blackkey and the key support mechanism in an exploded state;

FIGS. 6A and 6B are views useful in explaining operation of the whitekey in the keyboard device, in which FIG. 6A shows a key-released stateand FIG. 6B shows a key-depressed state;

FIG. 7A and 7B are views useful in explaining operation of the black keyin the keyboard device, in which FIG. 7A shows a key-released state andFIG. 7B shows a key-depressed state;

FIG. 8 is a view useful in explaining an essential part of the presentinvention, which is a perspective view of a first arm according to afirst embodiment in a state as viewed from below;

FIGS. 9A to 9C are views of the first arm and a cushion, in which FIG.9A shows a state immediately before the first arm moves into contactwith the cushion, FIG. 9B shows a state in which the first arm movesinto contact with the cushion and has crushed the cushion from above,and FIG. 9C shows a state in which a comparative first arm without afront-side protrusion is in contact with the cushion;

FIGS. 10A and 10B are views useful in explaining a first arm accordingto a second embodiment, which show a contact portion where the first armand the cushion contact each other, on an enlarged scale, in which FIG.10A and FIG. 10B show states similar to the states shown in FIG. 9A andFIG. 9B, respectively; and

FIGS. 11A and 11B are views useful in explaining a first arm accordingto a third embodiment, in which FIG. 11A and FIG. 11B show statessimilar to the states shown in FIG. 10A and FIG. 10B, respectively.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention will now be described in detail with reference tothe drawings showing preferred embodiments thereof. FIG. 1A shows onlyone octave section of a keyboard device 1 for an electronic piano towhich the present invention is applied. Note that in the following, adescription will be first given of the basic construction of thekeyboard device 1 and operation thereof, and then of an essential partof the present invention.

FIG. 1B shows a state of the keyboard device 1 shown in FIG. 1A, inwhich keys 2 other than a white key 2 a and a black key 2 b at the leftend of the keyboard device 1 are omitted. FIG. 2 shows a state of thekeyboard device 1 shown in FIG. 1B, in which the white key 2 a and theblack key 2 b are removed, together with respective key supportmechanisms 6 therefor, from a keyboard chassis 4.

This keyboard device 1 is comprised of the keyboard chassis 4, theplurality of keys 2 including the white keys 2 a and the black keys 2 band arranged in a state arranged side by side in a left-right direction,the plurality of key support mechanisms 6 each pivotally mounted on thekeyboard chassis 4, for supporting an associated one of the keys 2 frombelow, and key switches 3 each for detecting key depression informationof an associated one of the keys 2.

The keyboard chassis 4 includes a chassis body 4 a formed as a resinmolded article which is made e.g. by injection molding of apredetermined resin material (e.g. an ABS resin) into a predeterminedshape. As shown in FIGS. 3A and 3B, the chassis body 4 a has a frontportion 11, an intermediate portion 12, and a rear portion 13, eachextending in the left-right direction (in a left-right direction asviewed in FIG. 3A) as a whole. The front portion 11, the intermediateportion 12, and the rear portion 13 are integrally formed with eachother via a plurality of ribs 14 disposed with a spacing therebetween inthe left-right direction and each extending in the front-rear direction.Note that in the following description, the front portion 11, theintermediate portion 12, and the rear portion 13 of the chassis body 4 aof the keyboard chassis 4 will be referred to as “the chassis front 11”,“the chassis intermediate 12”, and “the chassis rear 13”, respectively.

The chassis front 11 is mainly for guiding the white key 2 a duringdepression thereof and restricting the upper limit position and thelower limit position of a front end of the white key 2 a. On the chassisfront 11, there are erected a plurality of white key guides 11 a, eachof which is inserted into each associated one of the white keys 2 a frombelow so as to prevent lateral swing of the white key 2 a, in a statearranged side by side in the left-right direction. Further, the chassisfront 11 has engagement holes 11 b and 11 b, vertically extendingtherethrough, which are formed on the left and right sides of each ofthe white key guides 11 a, respectively. A pair of left and right upperlimit position regulation portions 21 and 21, referred to hereinafter,of the white key 2 a are engaged with the respective engagement holes 11b and 11 b in a state inserted therethrough. Furthermore, the chassisfront 11 has a front end thereof formed with a stopper-mounting portion11 c that protrudes forward and extends along the entirety of thechassis body 4 a in the left-right direction. A key upper limit stopper16 a and a key lower limit stopper 16 b for the white key are mounted ona lower surface and an upper surface of the stopper-mounting portion 11c, respectively, such that they extend in the left-right direction. Notethat a stopper-mounting portion 11 d for the black key, which extendsalong the entirety of the chassis body 4 a in the left-right direction,is provided at a predetermined location of the chassis front 11,rearward of each white key guide 11 a, and that a key upper limitstopper 17 for the black key is mounted on the stopper-mounting portion11 d such that it extends in the left-right direction.

The chassis intermediate 12 is mainly for guiding the black key 2 bduring depression thereof and swingably supporting a first arm 31 and asecond arm 32, described hereinafter, of each of a white key-associatedkey support mechanism 6 a and a black key-associated key supportmechanism 6 b. The chassis intermediate 12 has a flat portion 12 a inthe form of a flat plate extending in the left-right direction, and aplurality of black key guides 12 b erected on the flat portion 12 a anddisposed with an appropriate spacing therebetween in the left-rightdirection. Each black key guide 12 b is inserted into an associated oneof the black keys 2 b from below to prevent lateral swing of the blackkey 2 b. Further, the chassis intermediate 12 has a front portionthereof provided with a first arm support portion 18 for supporting thefirst arms 31 of the key support mechanisms 6. The first arm supportportion 18 has a plurality of first pivot shafts 18 a each of which isprovided between each adjacent two of the ribs 14 and 14 such that thefirst pivot shaft 18 a extends in the left-right direction. The firstarms 31 are swingably supported on associated ones of the first pivotshafts 18 a. Furthermore, the chassis intermediate 12 has a rear portionthereof provided with a second arm support portion 19 for supporting thesecond arms 32 of the key support mechanisms 6. The second arm supportportion 19 has a plurality of second pivot shafts 19 a each of which isprovided between each adjacent two of the ribs 14 and 14 such that thesecond pivot shaft 19 a extends in the left-right direction. Theplurality of second pivot shafts 19 a are arranged on the same axisextending in the left-right direction at a location rearward of andhigher than the first pivot shafts 18 a, and the second arms 32 areswingably supported on associated ones of the second pivot shafts 19 a.Note that a first arm lower limit stopper 10 b extending along theentirety of the chassis body 4 a in the left-right direction is providedat a predetermined location of a middle rail 8, referred to hereinafter,disposed below the chassis intermediate 12.

Further, the above-mentioned key switches 3 are provided on a lowerportion of the keyboard chassis 4 between the above-described chassisfront 11 and chassis intermediate 12. The key switches 3 are formed by alaterally elongated printed circuit board 3 a extending in theleft-right direction, and a plurality of switch bodies 3 b formed byrubber switches attached to the printed circuit board 3 a on akey-by-key basis, for being pressed by associated ones of the first arms31 upon key depression.

The chassis rear 13 is mainly for guiding the keys 2 by their rear endsin the vertical direction while preventing lateral swing of the keys 2and for restricting the upper limit positions of the rear ends ofassociated ones of the first arms 31. As shown in FIGS. 2 and 3A, thechassis rear 13 has a plurality of partition walls 13 a formed with apredetermined spacing therebetween in the left-right direction so as toseparate each adjacent two of the keys 2 and 2 from each other. Further,as shown in FIG. 3B, a first arm upper limit stopper 10 a extendingalong the entirety of the chassis body 4 a in the left-right directionis provided at a predetermined location of an upper portion of thechassis rear 13. The first arm upper limit stopper 10 a and theabove-mentioned first arm lower limit stopper 10 b provided on thechassis intermediate 12 are for restricting the upper limit position andthe lower limit position of the first arm 31, respectively, when thefirst arm 31 having a function as a hammer for adding a touch weight tothe key 2 pivotally moves upward and downward. Furthermore, a metalcover plate 15 extending in the left-right direction along the entiretyof the chassis body 4 a and disposed to cover the rear ends of the keys2 is mounted on the upper portion of the chassis rear 13.

As shown in FIGS. 2 and 3A, the chassis body 4 a of the keyboard chassis4 constructed as described above is formed with a plurality of firstopenings 5 a open upward and forward and a plurality of second openings5 b open upward. The first arms 31 of the key support mechanisms 6 areengaged with associated ones of the first pivot shafts 18 a from outsidevia the above-mentioned first openings 5 a, respectively. Further, thesecond arms 32 are engaged with associated ones of the second pivotshafts 19 a from outside via the above-mentioned second openings 5 b,respectively.

Further, in the above-described keyboard chassis 4, a plurality ofchassis bodies 4 a are connected to each other so as to be arranged sideby side in the left-right direction, and are each screwed to a frontrail 7, the middle rail 8, and a rear rail 9 in a state placed thereon,the rails 7, 8 and 9 each extending in the left-right direction andarranged with a predetermined spacing therebetween in the front-reardirection. The keyboard chassis 4 is fixed to a keybed, not shown, ofthe electronic piano via the front rail 7 and the rear rail 9.

Next, the keys 2 and the key support mechanisms 6 will be described.FIG. 4A shows the white key 2 a and the key support mechanism 6 atherefor on an enlarged scale, and FIG. 4B shows them in an explodedstate. As shown in FIGS. 4A and 4B, the white key 2 a is formed e.g. byinjection molding of a predetermined resin material (e.g. an AS resin)into a hollow shape which extends a predetermined length in thefront-rear direction and opens downward. The white key 2 a has the frontend thereof formed with the pair of left and right upper limit positionregulation portions 21 and 21 which protrude downward from respectiveside walls of the front end of the white key 2 a and each having a lowerend thereof bent forward. As described hereinabove, the left and rightupper limit position regulation portions 21 and 21 are engaged with therespective left and right engagement holes 11 b and 11 b of the chassisfront 11 in a state inserted therethrough.

Further, at a predetermined location of a front portion of the white key2 a, rearward of the upper limit position regulation portions 21, thereis formed a key front-side connecting portion 22 connected to the firstarm 31 of the key support mechanism 6 a. This key front-side connectingportion 22 includes a connecting recess 22 a formed into a U shapehaving a slot-like shape in side view and open forward. Further, theconnecting recess 22 a has a cushioning member 20 attached thereto,which is formed to cover the whole inner peripheral surface of theconnecting recess 22 a, for suppressing generation of noise when aconnecting shaft 35 b, referred to hereinafter, of the first arm 31slides in the inner peripheral surface of the connecting recess 22 a.

Furthermore, the white key 2 a has a rear portion thereof provided witha key rear-side connecting portion 23 connected to the second arm 32 ofthe key support mechanism 6 a. The key rear-side connecting portion 23has a plate-like connecting body portion 23 a which hangs downward froma laterally central portion of the white key 2 a and has a predeterminedthickness in the left-right direction, and a pair of left and rightengagement protrusions 23 b and 23 b which coaxially protrude from theleft and right side surfaces of the connecting body portion 23 a,respectively. Further, the rear portion of the white key 2 a is formedwith a tool insertion hole 24 which vertically extends through the rearportion, and is used to insert a predetermined tool from above fordisconnecting the white key 2 a from the second arm 32 of the keysupport mechanism 6 a e.g. for maintenance of the keyboard device 1.

On the other hand, the key support mechanism 6 a includes the first arm31 and the second arm 32 which are engaged with each other and areconnected to the key front-side connecting portion 22 and the keyrear-side connecting portion 23 of the white key 2 a, respectively.

As shown in FIG. 4B, the first arm 31 is comprised of an arm body 33 andtwo weights 34 and 34 attached to the arm body 33. The arm body 33 isformed as a resin molded article which is made e.g. by injection moldingof a predetermined resin material (e.g. polyacetal resin) into apredetermined shape. This arm body 33 extends a predetermined length inthe front-rear direction, and has a front end thereof formed with afirst arm front-side connecting portion 35 connected to the keyfront-side connecting portion 22 of the white key 2 a. The first armfront-side connecting portion 35 includes a box portion 35 a having abox-like shape open upward and forward, and the connecting shaft 35 bprovided such that it extends in the left-right direction in a stateconnecting the front-side upper ends of left and right side walls of thebox portion 35 a to each other. The connecting shaft 35 b is connectedto the connecting recess 22 a of the key front-side connecting portion22 of the white key 2 a such that the connecting shaft 35 b is pivotallymovable and is slidable in the front-rear direction.

Further, the arm body 33 has a bearing portion 36 formed at apredetermined location immediately rearward of the first arm front-sideconnecting portion 35. The bearing portion 36 has an inverted U shapeopen downward in side view, and is pivotally engaged with the firstpivot shaft 18 a of the keyboard chassis 4. Furthermore, the arm body 33has a first arm rear-side connecting portion 37, which is connected tothe second arm 32, at a predetermined location rearward of the bearingportion 36. Specifically, the first arm rear-side connecting portion 37has a connecting shaft 37 a which extends in the left-right directionwith respective opposite ends thereof protruding outward from the leftand right side surfaces of the arm body 33. The opposite ends of theconnecting shaft 37 a are engaged with connecting recesses 45 b and 45 bof a second arm front-side connecting portion 45, referred tohereinafter, of the second arm 32.

The two weights 34 and 34 formed as elongated and narrow plates aremounted on a weight mounting portion 38, which is a rear portion of thearm body 33, in a state sandwiching the weight mounting portion 38. Notethat each weight 34 is made of a material (metal such as iron) having alarger specific gravity than the arm body 33, and is formed e.g. bypressing a metal plate into a predetermined shape.

The second arm 32 is formed as a resin molded article having apredetermined shape by injection molding of the same resin material asthat of the arm body 33 of the first arm 31. The second arm 32 isshorter than the first arm 31 and extends a predetermined length in thefront-rear direction. Further, the second arm 32 has a bearing portion41 having a C shape open forward in side view approximately at alongitudinal center thereof. The bearing portion 41 is pivotally engagedwith an associated one of the second pivot shafts 19 a of the keyboardchassis 4.

Further, the second arm 32 has a rear portion thereof provided with asecond arm rear-side connecting portion 42 connected to the keyrear-side connecting portion 23 of the white key 2 a. The second armrear-side connecting portion 42 is formed into a bifurcated shape, andhas two left and right connecting arm portions 43 and 43 which extend apredetermined length parallel to each other along the longitudinaldirection of the second arm 32. Each connecting arm portion 43 has arear end thereof formed with a connecting hole 43 a extending throughthe connecting arm portion 43 in the left-right direction. The twoconnecting arm portions 43 and 43 sandwich the connecting body portion23 a of the key rear-side connecting portion 23 of the white key 2 abetween the rear ends thereof from the left and the right, and eachconnecting hole 43 a has an associated one of the engagement protrusions23 b of the key rear-side connecting portion 23 pivotally fittedtherein.

Furthermore, the second arm 32 has a front portion thereof provided withthe second arm front-side connecting portion 45 connected to the firstarm rear-side connecting portion 37 of the first arm 31. The second armfront-side connecting portion 45 has a pair of left and right connectingportions 45 a and 45 a arranged with a predetermined spacing in theleft-right direction. The connecting portions 45 a and 45 a are eachformed with the connecting recess 45 b which has a U shape having aslot-like shape in side view and open forward. The left and rightconnecting portions 45 a and 45 a of the second arm front-sideconnecting portion 45 are pivotally and slidably engaged with therespective opposite ends of the connecting shaft 37 a of the first arm31 via the connecting recesses 45 b and 45 b thereof.

FIG. 5A shows the black key 2 b and the key support mechanism 6 btherefor on an enlarged scale, and FIG. 5B shows the black key 2 b andthe key support mechanism 6 b in an exploded state. The black key 2 b isformed e.g. by injection molding of the same resin material as that ofthe white key 2 a into a hollow shape which extends in the front-reardirection by a predetermined length shorter than that of the white key 2a and opens downward. The black key 2 b has a front-side lower endthereof provided with a key front-side connecting portion 26 formedsubstantially similar to the key front-side connecting portion 22 of thewhite key 2 a. This key front-side connecting portion 26 has aconnecting recess 26 a formed into a U shape having a slot-like shape inside view and open forward. Further, the key front-side connectingportion 26 has an extension portion 26 b on a lower-side front end ofthe connecting recess 26 a. The extension portion 26 b extends apredetermined length forward of the front surface of the body of theblack key 2 b. This extension portion 26 b functions as an upper limitposition regulation portion of the black key 2 b. Note that in thefollowing description, the components of the black key 2 b and the keysupport mechanism 6 b having the same configurations as those of theabove-described white key 2 a and key support mechanism 6 a are denotedby the same reference numerals and detailed description thereof will beomitted.

The key support mechanism 6 b supporting the black key 2 b isconstructed substantially similar to the above-described whitekey-associated key support mechanism 6 a. Specifically, the arm body 33of the first arm 31 of the key support mechanism 6 b and the second arm32 of the same are constructed exactly similar in shape and size to thearm body 33 and the second arm 32 of the white key-associated keysupport mechanism 6 a. Note that two left and right weights 34 and 34 ofthe black key-associated key support mechanism 6 b differ from theweights 34 of the white key-associated key support mechanism 6 a in theshape of the rear portion thereof.

Next, a description will be given of the operation of the keys 2 and thekey support mechanisms 6 of the keyboard device 1 constructed asdescribed above. FIGS. 6A and 6B are views useful in explaining theoperation of the white key 2 a and the key support mechanism 6 aassociated therewith. FIGS. 7A and 7B are views useful in explaining theoperation of the black key 2 b and the key support mechanism 6 bassociated therewith.

When the front end of the white key 2 a is depressed by a player withhis/her finger from a key-released state shown in FIG. 6A, the keyfront-side connecting portion 22 of the white key 2 a is moved downward,whereby the first arm 31 is pivotally moved in a counterclockwisedirection about the first pivot shaft 18 a. Further, in accordance withthe pivotal movement of the first arm 31, the second arm front-sideconnecting portion 45, which is engaged with the connecting shaft 37 aof the first arm 31 via the connecting recesses 45 b and 45 b, is movedupward. With this, the second arm 32 is pivotally moved in a clockwisedirection about the second pivot shaft 19 a. Then, in accordance withthis pivotal movement of the second arm 32, the key rear-side connectingportion 23, which is connected to the second arm 32 via the second armrear-side connecting portion 42 formed at the rear end of the second arm32, is pulled down, whereby the rear end of the white key 2 a is moveddownward.

Note that during the above-mentioned pivotal movement of the first arm31, the box portion 35 a of the first arm front-side connecting portion35 is moved downward, and accordingly, the switch body 3 b of one of thekey switches 3, which is associated with the depressed key 2, is pressedfrom above by the bottom wall of the box portion 35 a. As a consequence,in the electronic piano, key depression information of the depressed key2 is detected, and based on the detected key depression information,sound is generated from a speaker, not shown.

As described hereinabove, in the case where the white key 2 a isdepressed, in accordance with the counterclockwise pivotal movement ofthe first arm 31, the weight 34 of the first arm 31 is inclined suchthat the weight 34 becomes higher as it extends rearward, whereby therear end of the weight 34 is brought into contact with the first armupper limit stopper 10 a from below, as shown in FIG. 6B. This preventsfurther pivotal movement of the first arm 31. When the front end of thewhite key 2 a is depressed to its lowest position, the front end of thewhite key 2 a is brought into contact with the key lower limit stopper16 b, which blocks further depression of the white key 2 a.

The white key 2 a depressed as above operates such that it pivotallymoves about a virtual pivot P located rearward of the rear end thereof.The location of the virtual pivot P is set such that a distance from thefront end of the white key 2 a is approximately twice as long as thelength of the white key 2 a itself, for example. With this, when thefront end of the white key 2 a is depressed to the lowest position,compared with the case where the white key 2 a is in the key-releasedstate shown in FIG. 6A, the front end of the white key 2 a is positionedlower by a predetermined key stroke (e.g. 10 mm) and the rear end of thewhite key 2 a is located lower by a distance (e.g. 5 mm) which isapproximately half of the predetermined key stroke.

On the other hand, when the finger is released from the white key 2 abeing depressed, the first arm 31 of the key support mechanism 6 apivotally moves in a direction opposite to the above-mentioneddirection, by the own weight of the weight 34, and in accordancetherewith, the second arm 32 as well pivotally moves in a directionopposite to the above-mentioned direction. In accordance with thispivotal movement of the second arm 32, the white key 2 a pivotally movesupward about the virtual pivot P. Then, a predetermined portion of thefirst arm 31, rearward of the first pivot shaft 18 a, moves into contactwith the first arm lower limit stopper 10 b from above, and both of theupper limit position regulation portions 21 and 21 of the white key 2 amove into contact with the key upper limit stopper 16 a from below,whereby further pivotal movement of the white key 2 a is blocked and thewhite key 2 a returns to its original key-released state.

Further, when the black key 2 b is depressed, operations are performedsimilar to the above-described operations of the white key 2 a and thekey support mechanism 6 a. More specifically, when a front end of theblack key 2 b is depressed from a key-released state shown in FIG. 7A,the first arm 31 is pivotally moved in the counterclockwise directionabout the first pivot shaft 18 a, and the second arm 32 is pivotallymoved in the clockwise direction about the second pivot shaft 19 a. Withthis, the black key 2 b is operated such that it is pivotally movedabout a virtual pivot Q located rearward of the rear end thereof. Notethat similar to the above-mentioned virtual pivot P of the white key 2a, the location of the virtual pivot Q is set such that a distance fromthe front end of the black key 2 b is approximately twice as long as thelength of the black key 2 b itself, for example. Therefore, when thefront end of the black key 2 b is depressed to its lowest position,compared with a case where the black key 2 b is in the key-releasedstate shown in FIG. 7A, the front end of the black key 2 b is positionedlower by a predetermined key stroke and the rear end thereof ispositioned lower by a distance which is approximately half of thepredetermined key stroke.

On the other hand, when the finger is released from the black key 2 bhaving been depressed, the first arm 31 and the second arm 32 of the keysupport mechanism 6 b pivotally move in respective directions oppositeto the above-mentioned directions, and in accordance therewith, theblack key 2 b pivotally moves upward about the virtual pivot Q. Then,the extension portion 26 b of the key front-side connecting portion 26of the black key 2 b moves into contact with the key upper limit stopper17 from below, whereby further pivotal movement of the black key 2 b isblocked, and the black key 2 b returns to its original key-releasedstate.

Next, the essential part of the present invention will be described withreference to FIGS. 8 to 11B. The essential part of the present inventionis that the first arm 31 (hammer) of each key support mechanism 6supporting an associated one of the keys 2 from below is provided with acontact portion 33 a (predetermined portion) formed into a predeterminedshape for moving into contact with a cushion 51 associated with theabove-mentioned first arm lower limit stopper 10 b from above, and adeformation suppressing portion is provided on the contact portion 33 aand its vicinity, for suppressing deformation of the cushion 51 in thefront-rear direction.

FIG. 8 shows the first arm 31 according to a first embodiment of thepresent invention. As shown in FIG. 8 , the arm body 33 of the first arm31 is provided with the contact portion 33 a which moves into contactwith the cushion 51 from above, at a predetermined location of a bottomportion thereof, and a front-side protrusion 33 b (deformationsuppressing portion) which protrudes downward, at a location immediatelyforward (leftward in FIG. 8 ) of the contact portion 33 a. The contactportion 33 a extends a predetermined length in the front-rear directionand is formed flat. Further, the front-side protrusion 33 b is formedsuch that it is continuous with a front end of the contact portion 33 aand protrudes a predetermined length downward at approximately rightangles to the contact portion 33 a.

FIG. 9A shows a state immediately before the first arm 31 moves intocontact with the cushion 51 attached to the rear end of an upper surfaceof the middle rail 8 described above, and FIG. 9B shows a state in whichthe first arm 31 has moved into contact with the cushion 51 and hascrushed the cushion 51 from above.

As shown in FIG. 9A, the cushion 51 is formed of an elastic material,such as urethane, and extends a predetermined length along the middlerail 8 in the left-right direction (in a depth direction as viewed inFIG. 9A). The cushion 51 has a predetermined rectangular shape intransverse cross-section over the entire longitudinal length thereof,and an upper surface thereof is horizontal. Further, as shown in FIG.9A, the contact portion 33 a of the first arm 31 is formed such thatwhen the contact portion 33 a contacts the cushion 51, the contactportion 33 a is inclined downward toward the rear (inclined downward tothe right as viewed in FIG. 9A) with respect to the horizontal uppersurface of the cushion 51.

FIG. 9C shows a comparative first arm 31A which is different from thefirst arm 31 only in that the comparative first arm 31A does not havethe front-side protrusion 33 b, for comparison with the first arm 31. Inthis comparative first arm 31A, when the contact portion 33 a contactsthe cushion 51 from above, the contact portion 33 a progressivelycontacts the cushion 51 from the rear end toward the front end of thecushion 51. In this case, the contact portion 33 a of the comparativefirst arm 31A causes not only a downward force but also a force from therear to the front to act on the cushion 51. Therefore, the cushion 51 issometimes deformed forward as shown in FIG. 9C, and in this case, thereis a fear that the cushion 51 is hindered from properly exerting itsfunction as a cushion.

In contrast, in the case of the first arm 31 according to the presentembodiment, since the front-side protrusion 33 b is provided on thefront side of the contact portion 33 a, when the first arm 31 contactsthe cushion 51, the front-side protrusion 33 b moves onto the front sideof the upper end of the cushion 51. With this, as shown in FIG. 9B, whenthe first arm 31 contacts the first arm 31, it is possible to preventthe cushion 51 from being deformed forward, differently from theabove-described comparative first arm 31A. With this, it is possible tocause the cushion 51 to properly exert its function as a cushion.

Further, in the first arm 31 according to the present embodiment,similar to the above-described comparative first arm 31A, the contactportion 33 a progressively contacts the cushion 51 from the rear endtoward the front end of the cushion 51, and hence it is possible toprevent noise from being generated by the contact of the first arm 31with the cushion 51.

FIGS. 10A and 10B show where a first arm 31B according to a secondembodiment of the present invention contacts the cushion 51, on anenlarged scale. As shown in FIG. 10A, the first arm 31B according to thepresent embodiment is different from the first arm 31 according to thefirst embodiment only in that the contact portion 33 a has a rear-sideprotrusion 33 c provided at a rear portion thereof. This rear-sideprotrusion 33 c protrudes a predetermined length downward, and extendsalong the entirety of the arm body 33 of the first arm 31B in theleft-right direction. Further, the rear-side protrusion 33 c is set suchthat when the contact portion 33 a of the first arm 31B contacts thecushion 51, a distance between the rear-side protrusion 33 c and thefront-side protrusion 33 b is approximately the same as the length ofthe upper surface of the cushion 51 in the front-rear direction.

In the first arm 31B constructed as described above, when the contactportion 33 a thereof contacts the cushion 51, the upper end of thecushion 51 is restrained from the front and the rear by the front-sideprotrusion 33 b and the rear-side protrusion 33 c. With this, when thefirst arm 31B contacts the cushion 51, it is possible to effectivelysuppress deformation of the cushion 51 in the front-rear direction, asshown in FIG. 10B.

FIGS. 11A and 11B show where a first arm 31C according to a thirdembodiment of the present invention contacts the cushion 51, on anenlarged scale. As shown in FIG. 11A, the first arm 31C according to thepresent embodiment is different from the first arm 31 according to thefirst embodiment only in that the contact portion 33 a is provided witha fitting protrusion 33 d. The fitting protrusion 33 d is formed at alocation spaced rearward from the front-side protrusion 33 b by apredetermined distance. The fitting protrusion 33 d protrudes apredetermined length downward, and extends along the entirety of the armbody 33 of the first arm 31C in the left-right direction. Further,approximately at a center of the cushion 51 in the front-rear direction,a recess 51 a is provided which is formed to open upward with a depthapproximately equal to the protruding length of the above-describedfitting protrusion 33 d such that the recess 51 a extends along thelongitudinal direction of the cushion 51.

In the first arm 31C constructed as described above, when the contactportion 33 a thereof contacts the cushion 51, the fitting protrusion 33d of the first arm 31C is inserted into the recess 51 a of the cushion51 from above. With this, the first arm 31C contacts the cushion 51, itis possible to prevent the cushion 51 from being deformed in thefront-rear direction, as shown in FIG. 11B.

Note that the present invention is not limited to the above-describedembodiments, but it can be practiced in various forms. For example,although in the first embodiment, the front-side protrusion 33 b forpreventing the cushion 51 from being deformed forward is provided on thefront side of the contact portion 33 a of the first arm 31, for example,in a case where the contact portion 33 a of the first arm 31 is formedsuch that it is inclined downward toward the front, to prevent thecushion 51 from being deformed rearward when the contact portion 33 a ofthe first arm 31 contacts the cushion, it is preferable that anequivalent of the front-side protrusion 33 b is provided rearward of thecontact portion 33 a.

Further, although in the third embodiment, the fitting protrusion 33 dis provided on the contact portion 33 a of the first arm 31 according tothe first embodiment, it is also possible to omit the front-sideprotrusion 33 b. Even in the first arm thus constructed, similar to theother first arms, it is possible to prevent the cushion 51 from beingdeformed in the front-rear direction when the first arm 31 contacts thecushion 51.

Furthermore, although in the above-described embodiments, thedescription is given of a case where the present invention is applied tothe keyboard device 1 in which the keys 2 depressed operate such thatthey pivotally move about the virtual pivots P and Q located rearward ofthe rear ends of the keys 2, respectively, the present invention is notlimited to this, but as a matter of course, the present invention can beapplied to a general keyboard device in which keys are pivotally movedabout the rear ends of their own, respectively, and each of which is notprovided with the second arm 32. Further, details of the constructionsof the contact portion 33 a, the front-side protrusion 33 b, therear-side protrusion 33 c, and the fitting protrusion 33 d of the firstarms 31, 31B and 31C shown in the embodiments are given only by way ofexample, and they can be modified as appropriate within the scope of thesubject matter of the present invention.

It is further understood by those skilled in the art that the foregoingare preferred embodiments of the invention, and that various changes andmodifications may be made without departing from the spirit and scopethereof.

What is claimed is:
 1. A keyboard device for a keyboard instrument,comprising: a keyboard chassis; a key extending in a front-reardirection and disposed on the keyboard chassis; a hammer extending inthe front-rear direction and being pivotally supported, below the key,on the keyboard chassis, via a hammer support shaft, the hammer beingvertically pivotally moved in a manner interlocked with the key whichhas been depressed; and a cushion provided below the hammer and having apredetermined portion of the hammer placed thereon in a key-releasedstate, the predetermined portion of the hammer contacting the cushionfrom above when the hammer having been pivotally moved upward inaccordance with depression of the key returns to an original position inaccordance with release of the key, wherein the predetermined portion ofthe hammer is formed such that the predetermined portion is inclineddownward toward one side in the front-rear direction with respect to anupper surface of the cushion when the predetermined portion contacts thecushion, and wherein the hammer has a deformation suppressing portionprovided on the predetermined portion and/or its vicinity, forsuppressing deformation of the cushion in the front-rear direction whenthe hammer contacts the cushion.
 2. The keyboard device according toclaim 1, wherein the predetermined portion of the hammer is formed suchthat the predetermined portion is inclined downward toward a rear withrespect to the upper surface of the cushion when the predeterminedportion contacts the cushion, and wherein the deformation suppressingportion includes a downwardly protruding front-side protrusion on afront side of the predetermined portion.
 3. The keyboard deviceaccording to claim 2, wherein the deformation suppressing portionfurther includes a downwardly protruding rear-side protrusion on a rearside of the predetermined portion.
 4. The keyboard device according toclaim 1, wherein the cushion is provided with a recess open upward at aportion corresponding to the predetermined portion of the hammer, andwherein the deformation suppressing portion includes a fittingprotrusion formed on the predetermined portion such that the fittingprotrusion has a protruding shape protruding downward and is fittable inthe recess.